*Article* **Kiwi Fruits Preservation Using Novel Edible Active Coatings Based on Rich Thymol Halloysite Nanostructures and Chitosan/Polyvinyl Alcohol Gels**

**Constantinos E. Salmas 1,\* , Aris E. Giannakas 2,\* , Dimitrios Moschovas <sup>1</sup> , Eleni Kollia <sup>3</sup> , Stavros Georgopoulos <sup>2</sup> , Christina Gioti <sup>1</sup> , Areti Leontiou <sup>2</sup> , Apostolos Avgeropoulos <sup>1</sup> , Anna Kopsacheili <sup>3</sup> , Learda Avdylaj <sup>3</sup> and Charalampos Proestos 3,\***


**Abstract:** The concept of this study is the replacement of previous fossil-based techniques for food packaging and food shelf-life extension, with novel more green processes and materials following the spirit of circular economy and the global trend for environmentally positive fingerprints. A novel adsorption process to produce thymol-halloysite nanohybrids is presented in this work. The high dispersion of this thymol-halloysite nanostructure in chitosan biopolymer is one of the goals of this study. The incorporation of this biodegradable matrix with poly-vinyl-alcohol produced a very promising food-packaging film. Mechanical, water-oxygen barrier, antimicrobial, and antioxidant properties were measured. Transparency levels were also tested using a UV-vis instrument. Moreover, the developed films were tested in-vivo for the preservation and the extension of the shelf-life of kiwi fruits. In all cases, results indicated that the increased fraction of thymol from thyme oil significantly enhances the antimicrobial and antioxidant activity of the prepared chitosan-poly-vinyl- alcohol gel. The use of the halloysite increases the mechanical and water-oxygen barrier properties and leads to a control release process of thymol which extends the preservation and the shelf-life of kiwi fruits. Finally, the results indicated that the halloysite improves the properties of the chitosan/poly-vinylalcohol films, and the thymol makes them further advantageous.

**Keywords:** thyme oil; halloysite; chitosan; polyvinyl alcohol; gel; active coatings; nanostructures; kiwi fruits
